Method

Spread cut sides of baguette halves with cheese mixture. Arrange salmon, capers and onion in bottom half; replace top of loaf. Firmly press together. (Make-ahead: Wrap in plastic wrap and refrigerate for up to 24 hours or overwrap in foil and freeze for up to 1 week; thaw in refrigerator for 6 hours.) Cut into 1-inch (2.5 cm) thick slices.